Process for the catalytic production of olefin-sulphur dioxide compounds of high molecular weight



PM Apr. as, 1942 a 4mm UNITED STATES PATENT- OFFICE 2,280,818 PROCESS FOR THE. CATALYTIC PRODUC- -8ULPHUB DIOXIDE COMPOUNDS 'HIGII- MOLECULAR WEIGHT Frederick E. Frey, to: A. Schulre.

No Drawing.

rial No. 708,520.

Application itoberi Dewey Snow, and wu- Okla, llflsnors January 26, 1934, Se-

.Inne 8, 1938 17 Claims. (Cl. 260-94) This invention relates to the manufacture of compounds of high molecular weight by the reaction of sulphur dioxide with unsaturated organic compounds, and comprises processes for catalytically inducing or accelerating such reactions; all as more fully hereinafter set forth and as claimed.

The reaction of sulphur dioxide with conjugated diolefines is well known, and results in two products, one crystalline and one amorphous. The use of anticatalytlc compounds, and of high temperatures, has been claimed to favor the exclusive formation of the crystalline modification (Matthews and Strange, U. S. 1,192,259 (1916); Staudinger, Ger. 506,839 (1930) Perkins Can. 329,043 (1933).

The reaction of sulphur dioxide with mono oleflns was first reported by Matthews and Elder (Brit. 11,635, -1914) who formed amorphous products of high molecular weight by reacting some of the simpler oleflns with sulphur dioxide in the presence of sunlight or other source of actinic light. More recently, Fitch and Frey (Application Ser. No. 599,350, filed March 16, 1932, now U. 5. Patent 2,128,932 granted Sept. 6, 1938,) have described and claimed the process of inducing and carrying out these reactions in the absence of such source of light, by the use of suitable substances which exert a catalytic eiiect. Among such substances specifically claimed are oxygen and organic peroxides, salts of silver and monovalent copper, and oxides of nitrogen.

We have found that many other substances will induce and promote the reaction of sulphur dioxide with oleflns in the dark. Among such substances are many belonging to the following classes.

I Nitrates A. Inorganic (1) Metallic (2) Nitric acid (3) Ammonium nitrate (4) Nitrates 01' amino compounds,

such as NHlNO:

3. Organic (1) Alkyl, such as Cal-BNO: (2) Aryl (3) Nitrates of organic amines C. Organometallic, such as phenyl mercuric nitrate Mixtures of two or more above classes may be used, provided, of course, that they do not react with each other.

Inasmuch as the reaction between sulphur dioxide and the unsaturated compound occurs generally in the liquid phase, the catalytic substance must, either be soluble in the mixture of sulphur dioxide and unsaturated compound, or must react with one of its constituents to form an intermediate compound which is soluble in the reaction substances from the mixture. For example, silver nitrate, lithium nitrate, ammonium nitrate, and dilute alcoholic nitric acid, all of which are somewhat soluble in the reaction mixture, carry the reaction rapidly to completion. On the other hand, barium nitrate, zirconium nitrate, titanium nitrate, strontium nitrate and mercuric nitrate, all of which are relatively insoluble in the reaction mixture, do notstart the reaction at once, but after a period of induction extending over several days, the reaction begins, and goes to completion at a moderate rate. The fact that the reaction takes place after a period of induction would seem to indicate the possibility that there has been some chemical reaction between the insoluble added substance and something in the olefin-sulphur dioxide mixture to form a soluble catalyst.

The solubility of a catalytic substance may of course depend upon the presence of added materials or diluents in the reaction mixture, or upon the relative proportions of olefin and sulphur dioxide present. Consequently, an accurate. quantitative comparison of the effectiveness of various catalytic substances is diincult. However, the

data in the following table will indicate the comparative effectiveness ofseveral compounds when added in the amount of about 0.5 to 1.0 percent by we sht to a mixture of equal volumes of liquid sulphur dioxide and butene2.

Tan: I

Percentage conversion of bntene z to reaction product nitric acid- TABLE I-Continued Percentage conversion of butene 2 to reaction product Time 40 21 da. do.

46 da. da.

In the absence of any such substance, the conversion was never at any time appreciable.

We have also found that the soluble nitrates such as those of lithium or ammonium, or dilute nitric acid, are equally as eflective as silver nitrate. mol for mol. Furthermore, they have an 7 advantage in that they do not tend todiscolor the product as silver nitrate frequently does, and are not as liable to be precipitated from the reaction mixture by the presence of metals higher in the electromotive series.

We have found that the reaction products of nitric acid and the organic amines, such as n-butyl amine, di-n-butyl amine, tri-n-butyl amine, benzyl amine, and aniline, have much greater solubility in hydrocarbons, and mixtures of sulfur dioxide with hydrocarbons, than have most metallic salts, and that they are effective and suitable for the conduct of our process. Other substances having suitable catalytic properties, and favorable solubility in the reaction mixtures, arenitrolic acids, nitrolates, and pseudonitrols. These more soluble catalytic substances are especially suitable for use in our process 'when reacting sulphur dioxide with an unsaturated compound in the presence of inert diluents, such as paraflln hydrocarbons.

The above named substances may be conveniently added to the mixture to be reacted, in the form of a finely ground solid; or theymay be added in solution in alcohol or other inert organic solvent, and dispersed throughout the mixture by shaking or stirring.

The products obtained in our process with the use of these catalytic substances are practically identical with those obtained by reacting thesame unsaturated compound with sulphur dioxide ln the presence of sunlight.

Examples of the application of this process are:

I. Equimolecular solutions in absolute ethyl alcohol were prepared as follows: Saturated AgNOs, 1.6 g. LiNOs per 100 (20., 1.88 g. NHiNO: per 100 cc. One-half cc. of one of the solutions was added to a tube containing approximately g. of a mixture of SO: and butene-2. and the extent of the reaction was observed at various times after warming to room temperature and mixing. The data are given in the following table:

Percent conversion to reaction product Time, hours II. To a mixture of equal volumes of sulphur dioxide and oleilns contained in an autoclave or other pressure vessel is added from 0.01 percent to 0.1 percent, or more, by weight, of one of the substances shown above to exert a catalytic eflect upon the reaction. The catalytic substance is dissolved or dispersed throughout the mixture by thorough stirring or shaking, and the reaction is allowed to take place at temperatures within the range of 25 C. to +40 0.

III. To a mixture of equal volumes of allyl alcohol and sulphur dioxide is added 0.5 percent by weight of lithium nitrate. In a few days, in

the dark, the allyl alcohol is completely con verted to a solid, white polymer.

In the following claims the phrase soluble in the reaction mixture," or equivalent language, is

to be taken as including substances which are actually soluble in the reaction mixture as well as those which apparently react with the mixture to form soluble compounds having catalytic properties.

is Having described our invention, what we claim 1. The process of producing high weight heteropoiymers oi oleflns and sulphur dioxide which comprises conducting the reaction in the absence of actinic light in the presence of an active-oxygen-containing substance selected from the group consisting of nitrates other than silver nitrate, nitrites, perchlorates, chlorates,

persulphates and ozonides.

2. In a process in which oleflns are reacted with sulphur dioxide to form high molecular weight heteropolymeric products. the improvement which comprises eflfecting the reaction in the absence of actinic light by introducing into the reaction mixture an active-oxygen-containing substance soluble in the reaction mixture selected from the group consisting of nitrates other than silver nitrate, nitrites, perchlorates, chlorates, persulphates and ozonides.

3. The process of producing high molecular weight heteropolymers of oleilns and sulphur dioxide which comprises reacting oleflns with sulphur dioxide in the presence or a nitrate excepting silver nitrate.

4. The process of producing high molecular weight heteropolymers of oleflns and sulphur dioxide which comprises reacting a suitable olefin with sulphur dioxide in the absence of actinic light in the presence of a nitrate other than allver nitrate which is soluble in the reaction mixture.

5. In the process in which suitable oleflns are reacted with sulphur dioxide to form heteropolymeric products of high molecular weight, the improvement which comprises conducting the reaction in the absence of actinic light by incorporating in the reaction mixture a soluble nitrate ex-' cepting silver nitrate.

6. In the process in which oleiins are reacted .trate, nitrites,

with sulphur dioxide, said reaction normally occurring only in the presence oi. actinic light, to form heteropolymeric products of high molecular weight, the improvement which comprises eiIectv ing the reaction in the absence of actinic light by conducting the reaction in the presence or a small quantity of a nitrate or an alkali metal as a catalyst.

7. Process as in claim 4 in which the nitrate is an alkali metal nitrate.

8. In the process in which oleilns are reacted with sulphur dioxide, said reaction normally occurring only in the presence of actinic light, to form heteropolymeric products of high molecular weight, the improvement which-comprises eflecting the reaction in the absence oi. actinic light by conducting the reaction in the presence of. a

small amount or lithium nitrate as a catalyst.

9. Process as claimed in claim 3 in which the nitrate is lithium nitrate.

10. A process as claimed in claim 5 wherein the soluble nitrate is lithium nitrate.

11. Process as in claim 4 in which the nitrate is an organic compound.

12. Process as claimed in claim 3 in which the nitrate is an amino compound.

13. Process as in claim 4 in which the nitrate is an amino compound.

14. Process as claimed in claim 3 in which the nitrate is ammonium nitrate.

15. A process as claimed in claim 5 wherein the soluble nitrate is ammonium nitrate.

16. The process of producing high molecular weight heteropolymers oi. oleflns and sulphur dloxide, which comprises reacting oleilns with sulphur dioxide in the presence oi an activeoxygen-containing substance selected from the group consisting of nitrates other than silver niperchlorates, chlorates, persulphates and ozonides.

17. The process of producing high molecular weight heteropolymers oi! oleilns and sulphur dioxide, which comprises reacting olefins 1 with sulphur dioxide in the presence of an activeoxygen-containing substance soluble in the reaction mixture selected from the group consisting 01' nitrates other than silver nitrate, nitrites,

perchiorates, chlorates, persulphates and ozonides. I

FREDERICK E. FREY: ROBERT DEWEY SNOW. WALTER. A. SCHULZE. 

